Furnace wall



M. H. KUHNER FURNAC E WALL Filed April 18, 1935 INVENTOR 13 x H. KUHNER A'I I ORNEY a Patented Aug. 6, 1935 FURNACE WALL Max H. Kuhncr, Worcester, Mass, assigncr to Riley Stoker Corporation, Worcester, Mass., a corporation of Massachusetts Application April 18, 1933, Serial No. 666,708

6 Claims.

This invention relates to furnace walls, and more particularly to walls comprising heat absorbing tubes through which a fluid, such as water or steam, is circulated.

- In certain types of furnaces it is customary to utilize a Wall of refractory material and to pro tect this wall by means of parallel metal tubes located on the furnace side thereof. These tubes are usually connected at one or both ends to transverse headers, so that a suitable fluid can be circulated through the tubes to prevent them from being over-heated, and the headers are provided with removable hand-hole covers to facilitate A the rolling of the tubes into the headers and the 1-5 cleaning of the insides of the tubes. The handhole covers must be accessible from the outside of the furnace, and for this purpose it is customary to locate the headers outside the wall and to extend the tubes through the refractory material of the wall. There is always some movement of the tubes relative to the refractory material as a result of expansion and contraction with changes in temperature. This renders it practically impossible to maintain tight joints between the tubes and the refractory material,

even though flexible packing be provided around the tubes, and as a result air leaks into the furnace and lowers the efficiency of combustion.

It is accordingly one object of the invention to provide a simple and inexpensive furnace wall which will withstand high furnace temperatures and at the same time prevent all leakage of air into the furnace.

It is a further object of the invention to provide a simple, inexpensive and durable furnace wall comprising headers which are readily accessible from the outside of the furnace.

It is a further object of the invention to provide a simple and effective means which will prevent air leakage between a header and the refractory material of a furnace wall, and which will at the same time allow the parts to expand and contract freely with changes in temperature.

With these and other objects in view, as will 45 be apparent to those skilled in the art, the invention resides in the combination of parts set forth in the specification and covered by the claims appended hereto.

Referring to the drawing illustrating one embodiment of the invention, and in which like reference numerals indicate like parts,

Fig. 1 is a vertical section through a water cooled wall, the section being taken on the line Il of Fig. 2;

Fig. 2 is an elevation of a portion of the-wall viewed from the furnace side; and

Fig. 3 is an elevation of a portion of the wall, viewed from the outside of the furnace.

The embodiment illustrated comprises a vertical 8 wall it constructed of a suitable refractory material such as firebrick. ,Ahorizontal header l i is located within a recess 52 in the outside of the wall, and this header is supported by the brickwork beneath and supports in part the brickwork above. A series of metal tubes i i are connected to the header i l and extend inwardly toward the furnace through vertical slots or openings IS in the brickwork. These slots l5 extend from the recess 12 to the furnace side of the wall and they are shaped to provide an ample clearance space around the tubes so that the tubes cannot exert pressure against the brickwork as they move with changes in temperature. The tubes 54 are curved inwardly and upwardly from the header H, and after passing through the slots I5 they extend vertically upward along and close to the furnace side of the wall to protect the brickwork from the radiant heat. At their upper ends the tubes curve outwardly through slots 16 and connect with a horizontal header i8 located within a recess l9 in the outside of the wall. The constructions at the upper and lower ends or" the tubes are the same, except that the tubes approach the header H from above and the header is from below. However, it will be understood that the invention can be utilized in connection with a header at one end of the tubes only, and some other construction may be used at the opposite ends of the tubes.

The headers II and 18 are preferably circular in cross-section, since this shape is best adapted to withstand high internal pressures and it also allows the tubes to be connected at any convenient angle. However, the circular shape will not afford a good bearing for the brickwork, and I therefore weld or otherwise secure horizontal flanges 20 to the upper and lower surfaces of the headers. If these flanges contact directly with the brickwork, longitudinal expansion of the headers will tend to pull the bricks apart and open up cracks in the wall. In order to overcome this difficulty I provide flat metal plates 22 between the flanges 2d and the brickwork, and I preferably insert between the plates 22 and the flanges 20 flat sheets 23 of asbestos or other heat insulating material. I

In order that the tubes it may be conveniently rolled into the headers and subsequently cleaned internally when necessary, I provide each header with a row of suitable hand-hole covers or key caps 25. These key caps are located on the outer side of the headers in a readily accessible position. There is preferably one key cap opposite each of the tubes.

The operation of the invention will now be apparent from the above disclosure. A suitable fluid, such as hot water from a boiler (not shown), is delivered to the header H and flows upwardly through the tubes M, which are exposed to the radiant heat of the furnace. Some of the water is changed to steam, and the mingled steam and water flows from the tubes into the header 28, from whence it may be returned to the boiler. The tubes protect the refractory wall I!) to a considerable degree from the furnace heat. Longitudinal expansion of the tubes will be permitted by the flexibility of their curved end portions. The headers are free to expand longitudinally, and in so doing they will slide relative to the plates 22, which will prevent any tearing apart of the brickwork. The asbestos sheets 23 will prevent the transmission of heat between the headers and the plates. Since the headers are built into the wall, there is no possibility of air leakage between the headers and the brickwork, and the Wall will remain substantially air tight irrespective of expansion and contraction of the parts. The :ey caps 25 are readily accessible, and the entire construction is comparatively simple and inexpensive.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

.1. In combination with a substantially vertical furnace wall of refractory material, a substantially horizontal header embedded in the wall and shaped to provide substantially horiz'ontal top and bottom surfaces, said header being supported by the wall therebeneath and serving to support at least a part of the wall thereabove, metal plates above and below the header to prevent contact between the header and the refractory material, and a series of tubes connected to the header and extending along the furnace side of the wall.

2. In combination with a furnace wall of refractory material, a substantially horizontal header embedded in the wall, metal plates above and below the header to prevent contact between the header and the refractory material, heat insulating material between the plates and the header, and a series of tubes connected to the header and extending along the furnace side of the wall.

3. In combination with a substantially vertical furnace wall of refractory material, a substantially horizontal header embedded in the wall and shaped to provide substantially horizontal top and bottom surfaces, said header being supported by the Wall therebeneath and serving to support at least a part of the wall thereabove, metal plates above and below the header to prevent contact between the header and the refractory material, heat insulating material between the plates and the header, and a series of tubes connected to the header and extending along the furnace side of the wall.

4. In combination with a furnace wall of re fractory material, a substantially horizontal header embedded in the wall, the header being circular in cross-section and having horizontal flanges on its upper and lower surfaces, and a series of tubes connected to the header and extending along, the furnace side of the wall.

5. In combination with a furnace wall of refractory material, a substantially horizontal header located within a recess in the outer side of the wall, the header being circular in crosssection and having horizontal flanges on its upper and lower surfaces, a series of spaced openings extending from the recess to the furnace side of the Wall, and a series of tubes extending along the furnace side of the wall, each tube having an end portion which curves outwardly away from the furnace through one of the openings and connects with the header.

6. In combination with a substantially vertical furnace wall of refractory material, a substantially horizontal header located within a recess in the outer side of the wall and shaped to provide substantially horizontal top and bottom surfaces, said header being supported by the wall therebeneath and serving to support a part of the wall thereabove, a series of horizontally spaced openings extending from the recess to the furnace side of the wall, and a series of tubes extending along the furnace side of the wall, each tube having an end portion which curves outwardly away from the furnace through one of the openings and connects with the header, the openings being shaped to provide a clearance space around the tubes.

MAX I-I. KUHNER. 

